COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223

Understand

We present accurate time delays for the quadruply imaged quasar HE 0435-1223.

• The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010.
• With seven years of data, we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expressed relative to quasar image B.
• We measured Delta_t(BC) = 7.8+/-0.8 days, Delta_t(BD) = -6.5+/-0.7 days and Delta_t_CD = -14.3+/-0.8 days.